Theoretical Investigation of the Hydrolytic Mechanism of α-Functionalized Alkoxysilanes as Effective Crosslinkers and the Difficulty of Deep Vulcanization in RTV Silicone Rubber

• Main Authors: Huihui Xu, Yanhong Gao, Zihou Liu, Yiling Bei
• Format: Article
• Language: English
• Published: MDPI AG 2018-08-01
• Series: Materials
• Subjects: α-, γ-ethylenediaminemethyl trimethyl-ketoxime silane; hydrolytic activity; ab initio calculation; density functional theory; RTV silicone rubber
• Online Access: http://www.mdpi.com/1996-1944/11/9/1526
• ISSN: 1996-1944

The reactions between α-, γ-ethylenediaminemethyl trimethyl-ketoxime silane (α-, γ-EAMOS) and H2O were investigated on the geometries of stationary points, the reaction pathway (IRC), thermodynamic and kinetic analysis by density functional theory (DFT) at the B3LYP/6-311G (d, p) level. Interestingly, the results showed that the hydrolysis activity of α-EAMOS is higher than that of γ-EAMOS, due to the influence of an amino substituent in position α-C on silicon. α-EAMOS can be used as a superior crosslinker for room temperature vulcanized (RTV) silicone rubber to achieve rapid crosslinking without a toxic catalyst. Besides, compared with the reaction between α-EAMOS and H2O, the reactivity between α-EAMOS and hydroxy siloxane (HO–Si(CH3)2–OSiH3) was discussed. Particularly, it revealed that the deep vulcanization of RTV silicone rubber is difficult.